Portable back rest or similar article



FIG. 1 is a perspective view of a portable back rest or similar article showing my design in position for use;

FIG. 2 is a view in front elevation showing my design in position for storage and;

FIG. 3 is a rear elevational view thereof.

The dotted line showing of a seat fragment in FIG. 1 is for illustrative purposes only. 

The ornamental design for a portable back rest or similar article, as shown and described. 